linking a gallery on the main page to an existing gallery

hi there, My question is: Could I use only 3 galleries to populate the first home page?

i understood that the main page (with the mosaic) is made by all created galleries. i managed to create them, however I would like to have only 3-4 galeries maximum. Here, I had to create 8-9 galleries just to populate that page. One other way would be to link some images of the first page to a common gallery. Could you help me here? my website: www.carolinekuhne.be. thanks!